Week 2

A breakthrough in the code

After many painful hours of trying to ‘fix’ the python program so that it could reproduce the luminosities from count rate found in the reference paper, it became apparent that it wasn’t that our program didn’t work, but that the reference catalogue contained quantities calculated with a different cosmology. It’s safe to say we were more than thrilled to have a working program at last, all credit to the man of the hour, Ben, of course. The next course of action with the code was to calculate black hole accretion rates (BHARs) for the X-ray data which was achieved by the end of the lab session.

Continuing the classification of the sources based on morphology, we looked at the X-ray data in DS9 for the sources that were not in the Hubble field and tried to classify them based off this. However, it was pointed out to us that galaxies are going to look different in different wavelengths so classifying them based on how they look in X-ray or radio will not give comparable results to the ones that have been classified in the optical. We made the decision to put galaxies with no Hubble image into the ‘4’ category. All fours will be discarded when investigating the relationship between morphology and BHAR.

After classifying all the galaxies we have in X-ray and Radio we compared the two sets and found that they have very similar fractions of each type of morphology. A quick conclusion from this is that morphology does not affect/ is not affected by the type of radiation the galaxy is detected in.

Most of the sources are either compact (1) or point-like (0) in both radio and X-ray, type 4 galaxies are ignored in morphology analysis as they represent unclassifiable sources.

All the X-ray and radio detected sources are AGN, as their luminosities in their respective bands exceed by a large margin the typical luminosities of a star forming galaxy (SFG). In the X-ray for example, all of our sources have a luminosity exceeding 10^42 ergs^-1, this would correspond to a star formation rate of 1000 solar masses per year, far in excess of a typical SFG, meaning this X-ray emission must be from an AGN source. 

There are a total of 258 X-ray sources and 121 radio sources (57 of these are also detected in the X-ray so represent the same source).

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